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DS90UB935-Q1: time from PDB to I2C

Elec Cheng
Expert 7055 points
Part Number: DS90UB935-Q1


Hi Expert,

As you can see below, the minimal delay time from PDB to I2C ready is 2ms. The I2C ready means Des can access and config 935 register, right? Is it ready for  remote I2C? If we want to access remote I2C slave, such as sensor, how long is the delay between PDB and remote I2C ready? Now we have seen an issue that, we need to wait 800ms after PDB high then SoC can access remote I2C, such as sensor. Please help give your understanding. Thanks.

BR,

Elec Cheng

  • 0
    TI__Guru 66880 points

    Hi Elec, 

    I2C ready in this case means that device is properly strapped, out of power-on/reset state, and eligible for local I2C writes. For remote I2C from DES, successful lock is also required. 

    If customer is having abnormally long delay time requirements of 800ms, then this is likely a sequencing and/or script timing issue. For further comment, we would need power sequencing (PDB of SER and DES), lock, and I2C signals side-by-side to further diagnose. I suspect there is an issue where SER PDB is before DES's, lock isn't successful yet, etc.

    Regards, 

    Logan